--- title: Claude’s new system prompt really doesn’t want to... description: Anthropic updated the published system prompt for Claude Fable 5.1, adding strict new rules against reproducing song lyrics, poems, and book passages, and... canonical: https://daily.dev/posts/claude-s-new-system-prompt-really-doesn-t-want-to-reproduce-song-lyrics-4c5sjaqx2 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Claude’s new system prompt really doesn’t want to reproduce song lyrics | daily.dev og:description: Anthropic updated the published system prompt for Claude Fable 5.1, adding strict new rules against reproducing song lyrics, poems, and book passages, and... og:url: https://daily.dev/posts/claude-s-new-system-prompt-really-doesn-t-want-to-reproduce-song-lyrics-4c5sjaqx2 og:image: https://api.daily.dev/og/posts/4c5SjaqX2.png og:image:alt: Claude’s new system prompt really doesn’t want to reproduce song lyrics og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Claude’s new system prompt really doesn’t want to reproduce song lyrics **[Simon Willison](https://daily.dev/sources/simonwillison)** · 11 min read · 0 upvotes · 0 comments ## Summary Anthropic updated the published system prompt for Claude Fable 5.1, adding strict new rules against reproducing song lyrics, poems, and book passages, and against generating copyrighted characters, logos, or artwork (even via SVG/code). The update also softens the abusive-user handling (no longer instructing Claude to threaten ending the conversation), adds harm-reduction drug guidance pointing to third-party sites like dancesafe.org, tightens response brevity, and bans phrases like 'genuinely' and 'honestly'. The reliable knowledge cutoff is now June 2026. Notably, some behavior (like the end_conversation tool) is driven by unpublished prompt layers not shown in the public docs. The author also built a GitHub-based tool that tracks and diffs these system prompt changes over time, with an LLM (GPT-5.6 Luna) generating changelog summaries. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Does Claude's system prompt now ban reproducing song lyrics? Yes, the Fable 5.1 system prompt added a section explicitly stating Claude does not reproduce song lyrics, poems, or passages from books and articles in whole or in part, including choruses, hooks, or lines pasted in one at a time. Once Claude declines such a request, it keeps declining reworded versions for the rest of the conversation, though works published before 1929 are exempt. _daily.dev helps developers building on Claude track prompt policy shifts like new copyright restrictions._ ### Why did Anthropic add rules against reproducing song lyrics to Claude's system prompt? The rules were added within days of news that Sony Music Publishing and Warner Chappell sued Anthropic for training Claude on databases of song lyrics, suggesting the new prompt restrictions are a response to that litigation. The prompt now also forbids generating copyrighted characters, logos, or artwork, even through code-based drawing like SVG or CSS. _Track how legal pressure reshapes AI model behavior alongside daily.dev when evaluating tools like Claude._ ### What is Claude Fable 5.1's reliable knowledge cutoff date? Claude Fable 5.1's reliable knowledge cutoff, past which it cannot answer reliably, is the end of June 2026, which is also listed as its training data cutoff. The system prompt instructs Claude to answer as a highly informed individual from June 2026 would, and to say so when relevant. _daily.dev keeps developers current on model cutoff dates that affect how they trust Claude's answers._ ## Similar posts on daily.dev - [Changes in the system prompt between Claude Opus 4.6 and 4.7](https://daily.dev/posts/changes-in-the-system-prompt-between-claude-opus-4-6-and-4-7-g5kfwybsl) · Simon Willison · 3 upvotes · 0 comments --- Tags: [#claude](https://daily.dev/tags/claude), [#anthropic](https://daily.dev/tags/anthropic), [#prompt-engineering](https://daily.dev/tags/prompt-engineering), [#ethical-ai](https://daily.dev/tags/ethical-ai) [View this post on daily.dev](https://daily.dev/posts/claude-s-new-system-prompt-really-doesn-t-want-to-reproduce-song-lyrics-4c5sjaqx2) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Claude’s new system prompt really doesn’t want to reproduce song lyrics","url":"https://daily.dev/posts/claude-s-new-system-prompt-really-doesn-t-want-to-reproduce-song-lyrics-4c5sjaqx2","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/claude-s-new-system-prompt-really-doesn-t-want-to-reproduce-song-lyrics-4c5sjaqx2"},"datePublished":"2026-09-02T14:17:23.140Z","dateModified":"2026-09-02T14:41:57.041Z","description":"Anthropic updated the published system prompt for Claude Fable 5.1, adding strict new rules against reproducing song lyrics, poems, and book passages, and...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/f041a89295b44e1a21537a44ab030942?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/f041a89295b44e1a21537a44ab030942?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Simon Willison","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Simon Willison","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/cf12b897300740218b35f49a6309ec5b","url":"https://daily.dev/sources/simonwillison"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/claude-s-new-system-prompt-really-doesn-t-want-to-reproduce-song-lyrics-4c5sjaqx2","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"claude,anthropic,prompt-engineering,ethical-ai","timeRequired":"PT11M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Simon Willison","item":"https://daily.dev/sources/simonwillison"},{"@type":"ListItem","position":3,"name":"Claude’s new system prompt really doesn’t want to reproduce song lyrics"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/claude-s-new-system-prompt-really-doesn-t-want-to-reproduce-song-lyrics-4c5sjaqx2#faq","mainEntity":[{"@type":"Question","name":"Does Claude's system prompt now ban reproducing song lyrics?","acceptedAnswer":{"@type":"Answer","text":"Yes, the Fable 5.1 system prompt added a section explicitly stating Claude does not reproduce song lyrics, poems, or passages from books and articles in whole or in part, including choruses, hooks, or lines pasted in one at a time. 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